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Quantitative relationship of spore and plant assemblages from the Radnice Basin, Middle Pennsylvanian of the Czech Republic : preliminary results

100%

Bek J. , Opluštil S. , Pšenička J. , Votočková-Frojdová J.

tom Vol. 65, No. 4

205--215

Dispersed miospore and pollen assemblages are described from the Radnice Basin, Middle Pennsylvanian, Czech Republic. Conversion factors (R-values) were produced by comparing the palynological data with quantified macrofloral data, to relate the percentages of spore/pollen taxa to those of the major plant groups that produced them. Among arborescent lycopsids, the miospore and macroplant counts are more or less equal. In other lycopsids miospores are strongly over-represented, as their macroplant remains were relatively fewer than would be suggested by the proportion of their spores in miospore spectra. Sphenophyll and calamitid macroplants were also relatively fewer than are their spores as a proportion of palynological spectra. By contrast, macroplants of ferns and cordaites are relatively more numerous than are their miospores and pollen in palynological spectra.

The relationship of brine chemistry of the Pennsylvanian Paradox Evaporite Basin (southwestern USA) to secular variation in seawater chemistry

88%

Petrychenko O. Y. , Williams-Stroud S. , Peryt T. M.

2012

tom Vol. 56, No 1

25--40

To establish the brine chemistry associated with the evaporites in the Pennsylvanian Paradox Basin of southeastern Utah and southwestern Colorado (USA), the composition of primary fluid inclusions was determined for sedimentary halite from two drill cores, one near the central part of the basin (Shafer Dome No. 1) and one from a more marginal location of the basin (Gibson Dome No. 1). Chemical analysis of halite fluid inclusions was done on six samples from three different evaporite cycles of the Paradox Formation; cycle 10 in the Shafer Dome core and cycles 6 and 18 from the Gibson Dome core. The inclusions that range in size from 2 to 80 microns across, were analyzed using the Petrychenko method. Large inclusions (40 to 80 microns across) that were used for the chemical analyses contain one fluid phase with a carnallite or sylvite daughter crystal. Also reported in this study are fluid inclusion homogenization temperatures for sylvite or carnallite from primary halite crystals in the Gibson Dome core and in Shafer Dome. The relationship between K+ and Mg2+ in chloride rich inclusions corresponds to their proportion in MgSO4-depleted marine waters concentrated to the stage of carnallite deposition. A correlative relationship was observed between K+2+4-rich to MgSO4-poor compositions that have been proposed by other workers. A transition from MgSO4-rich to MgSO4-poor seawater composition may have occurred between Pennsylvanian and Permian times. This paper presents a possible alternate explanation to those already proposed in the literature, that the Paradox Formation mineralogy resulted from an intermediate seawater composition that records the global transition from MgSO4-rich to MgSO4-poor seawater.

Sedymentacja osadów węglonośnej sukcesji Górnośląskiego Zagłębia Węglowego : kierunki badań i aktualny stan wiedzy

63%

Gradziński R. , Doktor M. , Kędzior A.

tom Vol. 53, nr 9

734-741

The coal-bearing succession in the Upper Silesia Coal Basin consists of molasse deposits filling a flexural foredeep basin. Analysis of lithofacies in cores from deep boreholes revealed the presence of depositional environments typical of alluvial plains and coastal (in a broad sense) environments. Accumulation compensated regional subsidence, so that general depositional surface remained nearly flat. The higher part of the csuccession was laid in fluvial systems, while the lower part mostly in fluvial systems and subordinately in complex coastal systems. Reconstruction of depositional architecture has shown lateral variation in thickness and extent of individual lithosomes, and also pointed to the role of peat-compaction control in shaping their 3D geometry. Sedimentation was controlled by both autigenic and allogenic factors.

The dentition of a eugeneodontiform shark from the Lower Pennsylvanian of Derbyshire, UK

51%

Ginter M.

nr 4

The anterior part of a medium-sized shark surrounded by hundreds of ostracod shells was found at the end of the last century in a dark limestone nodule from the Kinderscoutian (Bashkirian, Pennsylvanian) near Carsington, Derbyshire (England, UK). The shark is a caseodontoid eugeneodontiform, most probably belonging to Campodus agassizianus. Its dentition is of the crushing type, highly heterodont, but the symphyseal tooth whorl, typical of the most of eugeneodontiforms, was not found. The teeth are symmetrical labio-lingually which is unique in this group. The analysis of the available data leads to the conclusion that neither the tooth whorls of “Campodus variabilis” sensu Eastman, nor the mandibular dentition of “Agassizodus variabilis” sensu St. John and Worthen represent the genus Campodus and that these specimens deserve a new, probably common, name.